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I built a linux (Ubuntu) box a year ago and decided to have some fun and use a soft RAID 5. I followed the instructions here.

Things seemed to work fine, but now it's time to reformat the computer and start with the newest version of Ubuntu.

I get to the partition part of the install and run into problems. The system sees my RAID 5 (md0), I just can't seem to get it to reformat that raid.

I have 3 1TB drives (so I get 2TB of storage). All 3 are raided up. First off, is that ok? Having all my drives in the same array (including the boot). It seemed silly to me to raid a block of drives but not have the boot drive raided, because then if the boot drive failed the RAID would be dead anyway. Or is that thinking wrong? I ask because the tutorial I linked to said the /boot drive has to be on a type 1 array.

During the partition portion of the installation, the only thing I can find to "delete" the raid is an option to erase the raid. The next screen says that random bits will be written to the drives and the RAID will be gone. I'm guessing this process could take some time, but I started it 30 minutes ago and it isn't even reporting as being 1% done.

Is there an easy way to just delete the RAID partition, then recreate the RAID (I don't need the drives erased, just a quick reformat would do).



I posted this on superuser too. Didn't realize this forum existed. Sorry

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closed as too localized by Stefano Palazzo Jan 21 '12 at 16:41

This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.

To your first question, no it is not a problem; grub2 does not require a separate /boot partition. It sounds like you originally installed using the alternate cd and are now trying to install using the live cd. The live installer is a bit buggy in this regard, and will not let you install to /dev/md0 unless you partition it, and then install to /dev/md0p1. If you use the alternate installer, you should be able to set md0 to be used for / and to be formatted during the install.

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I was using the alternate CD the second time around. Don't know why it was being so finicky. The instructions/screens have changed a bit, but I finally got it working. Thanks for the info though! – Tyler DeWitt Oct 25 '11 at 4:13

It's generally recommended to have the boot/os drive seperated from the storage array - then setup a rsync cron job (to backup the os conf onto the array).

This allows one to easily format / upgrade / change distributions on the OS drive, and easily re-mount the mdadm array.

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You can remount an mdadm array even if the boot drive is different? The array contains all the info it needs to be mounted? – Tyler DeWitt Oct 25 '11 at 0:29
Where did you see this recommended, because it is not a good idea. – psusi Oct 25 '11 at 3:36
In my mind it seemed like a good idea to put the OS on a RAID array because I thought if the OS drive went out then the system was SOL. Is that not the case? Can I just remount the array with a different OS if I install the OS to a non raided partition? I thought the OS controlled the RAID – Tyler DeWitt Oct 25 '11 at 4:13
Yeah - thats one of the great things about an mdadm array - you can use --assemble and mount it on other systems. – Thermionix Oct 25 '11 at 6:54

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